U.S. women suffragists demonstrating in 1913. By the early 1900s, the term 'feminism' had become associated particularly with the women’s suffrage movement.

The earliest citation for the word feminism that we currently have comes from one of our own dictionaries: an 1841 edition of Noah Webster’s American Dictionary of the English Language contains an entry for feminism, with the definition “the qualities of females.” The word also had a medical meaning in use during the 1800s. However, these meanings of feminism are now exceptionally rare, and not entered in most dictionaries.

There are two current senses of feminism entered in our dictionaries, and they appear to have originated in the 1890s.

From Brussels, Belgium, Prof. Luis Bridel writes that feminism is gaining ground from year to year in his and all civilized nations. From an economic point of view he claims for women, in particular, equal wages for equal work, protection for women in factories and shops, domestics and waiters, etc.— The Daily American (Nashville, TN), 24 May 1893

The rights of women were a topic of much discussion and debate in America and France during the 1800s, though the earliest discussions regarding what came to be called feminism dealt primarily with theory (which accounts for the wording of our first definition: “the theory of the political, economic, and social equality of the sexes”). But as women’s rights moved from theory to reality, feminism came to refer to the organized actions of those advocating for the rights of women in the workplace, home, and voting booth. By the early 1900s, the word feminism had become associated particularly with the women’s suffrage movement:

Woman Suffrage Is Feminism!The whole suffrage movement is kept active by a few agitators. Many of these “leaders” are feminists, the ballot being a mere way-station.— advertisement placed by the Rochester Association Opposed to Women Suffrage in The Rochester (New York) Democrat and Chronicle, 16 Oct. 1914

This meaning, “organized activity on behalf of women's rights and interests,” has gained ground in the last century, though the theoretical use is still very common.